3.3 Pain
- Syllabus
- 9990–2028–2029
- Topic
- 3.3
- Level
- A2
Learning objectives
3.3.1Types and theories of pain• 3.3.1 Types and theories of pain- functions of pain; types of pain: acute and chronic pain. Focus on phantom limb pain and mirror treatment to include a case study, e.g. MacLachlan et al. (2004).- theories of pain: specificity theory, gate control theory.- Relevant issues and debates and methodology for this topic include: individual and situational explanations, nature versus nurture, reductionism versus holism, determinism versus free-will, case study.3.3.2Measuring pain• 3.3.2 Measuring pain- subjective measures including clinical interview.- psychometric measures and visual rating scales:- - McGill pain questionnaire- - visual analogue scale (exemplified by the following key study). Key Study on comparing pain assessments by doctors, parents and children: Brudvik et al. (2016).- behavioural/observational measures: UAB pain behaviour scale.- Relevant issues and debates and methodology for this topic include: idiographic versus nomothetic, quantitative and qualitative data, interviews, observations, psychometrics, generalisations.3.3.3Managing and controlling pain• 3.3.3 Managing and controlling pain- biological treatment: biochemical.- psychological treatments: cognitive strategies (attention diversion, non-pain imagery and cognitive redefinition).- alternative treatments: acupuncture; stimulation therapy/TENS.- Relevant issues and debates and methodology for this topic include: application to everyday life, cultural differences, reductionism versus holism, determinism versus free-will, idiographic versus nomothetic, objective and subjective data.
Pain signals tissue threat, but the experience is modulated
| Pain type/function | Pattern | Important boundary |
|---|---|---|
| Protective function | Warns of actual/potential harm, promotes withdrawal/rest and learning | Pain can persist after protection is useful, and damage can occur with little pain |
| Acute | Rapid onset, usually identifiable source/location and short duration; often resolves with healing/treatment | Intensity can be high but duration, not severity alone, defines it |
| Chronic | Persists beyond expected healing/for an extended period and can affect mood, relationships and quality of life | May begin as acute pain; biological, cognitive and social processes maintain it |
| Phantom limb | Pain is experienced as located in an amputated limb | The experience is real although the peripheral limb is absent |
| Theory | Mechanism and prediction | Evaluation |
|---|---|---|
| Specificity | Specialised pain receptors/pathways carry signals to a pain centre; more noxious input should produce more pain | Explains sensory transmission but is reductionist: damage and reported pain often diverge |
| Gate control (Melzack & Wall) | In the spinal dorsal horn, relatively greater small-fibre activity opens transmission while large touch/pressure fibres inhibit it; descending attention, emotion and expectation can also modulate perception | Explains rubbing an injury and psychological strategies, integrating nature/nurture; ‘gate’ is a model, not a conscious door |
| MacLachlan, McDonald & Waloch (2004) | Evidence map |
|---|---|
| Problem/method | First reported therapeutic mirror treatment case for ongoing lower-limb phantom pain in a conventional clinical setting |
| Procedure | The intact leg and its mirror reflection created visual feedback of two limbs while repeated movements were performed; practice later progressed without the mirror |
| Result | Phantom pain reduced significantly during intervention, perceived motor control increased, and aspects of the phantom changed |
| Inference/limit | Congruent visual–motor feedback may alter phantom experience. One male case gives rich idiographic/process evidence but cannot prove efficacy, mechanism or generalisation |
Specificity emphasises biological nature and determinism; gate control is more holistic because sensory input interacts with learned attention, expectation and emotion. Mirror treatment gives the person active control, but improvement still depends on neural and situational processes rather than free will alone.
Pain is neither ‘only in the tissue’ nor ‘only in the mind’. Gate control explains modulation of genuine nociceptive experience; MacLachlan supports treatment potential for one lower-limb case, not a universal cure.
Pain measures capture different perspectives, not one perfect score
| Measure | What it captures | Strength | Limitation |
|---|---|---|---|
| Clinical interview | Patient's location, quality, timing, triggers and meaning through questions | Flexible, idiographic qualitative detail and clarification | Vocabulary, memory, social desirability and practitioner bias; no standard precise score |
| McGill Pain Questionnaire | Sensory, affective and evaluative descriptors; pain-rating index, words chosen and present intensity 1–5 | Multidimensional yet quantitative; standardised comparison | Fixed descriptors may not fit language/culture or unique experience |
| Visual/faces rating scale | Child/adult marks a line, number or age-appropriate face for intensity | Quick, repeatable and directly self-reported | Scale understanding and anchors differ; number remains subjective |
| UAB Pain Behavior Scale | Observer rates categories such as vocal complaints, grimacing, posture, mobility and guarding | Adds visible behaviour and standardised observation | Pain can be hidden/exaggerated; observer inference and context affect score |
| Brudvik et al. (published 2016/2017) | Evidence map |
|---|---|
| Design/sample | Cross-sectional Bergen emergency outpatient study of 243 children aged 3–15 with independent child, parent and physician ratings |
| Measures | Age-appropriate child scales (faces/colour for younger children; visual analogue for older children) and parent/physician numerical ratings |
| Results | Mean child pain 5.5, parent 4.8, physician 3.2; child–parent agreement moderate (κ=.55), child–doctor .12 and parent–doctor .17. Underestimation was less marked for fractures |
| Conclusion | Physicians commonly underestimated paediatric pain; child self-report plus parent assessment can improve decisions |
| Strength | Limitation |
|---|---|
| Real emergency setting and three independent perspectives improve ecological/construct coverage | Cross-sectional ratings cannot reveal which estimate caused treatment or which is an objective ‘truth’ |
| Age-adapted standard scales and quantitative agreement support comparison | Scales differ by age; illness mix, Norwegian setting and observer expectations constrain generalisation |
| Exact disagreement has direct pain-management application | Severe pain can impede completion, and hardly half of severely affected children received relief—rating alone does not ensure action |
Choose by purpose: interview for quality/context, McGill for multidimensional standard scoring, visual scale for rapid self-rated intensity, and UAB for observable behaviour. Combine them when decisions are high-stakes; investigate disagreement rather than averaging away the patient's voice.
Quantitative does not mean objective, and observational does not mean accurate. Pain has no simple external gold standard: validity improves when age, language, behaviour, self-report and clinical context are considered together.
Pain management targets chemistry, attention or sensory modulation
| Route | Mechanism/use | Strength | Risk/boundary |
|---|---|---|---|
| Biochemical | Analgesic/anti-inflammatory or neuropathic-pain medicine changes peripheral/CNS signalling; e.g. gabapentin may help some nerve/phantom pain | Convenient, standardisable and may act quickly | Side effects, tolerance/dependence for some drugs, interactions; suppresses pain rather than every cause |
| Attention diversion | Actively (singing/task) or passively (picture/TV) focus limited attention away from pain | Portable, active patient control, no drug side effects | Severe/chronic pain may dominate attention; relief varies |
| Non-pain imagery | Generate a vivid safe/pleasant scene incompatible with sustained pain focus/arousal | Can reduce distress and descending amplification | Requires concentration/practice; not tissue repair |
| Cognitive redefinition | Reframe sensations as manageable, temporary or non-threatening rather than catastrophic | Alters appraisal, anxiety and coping | Unsupported reassurance may invalidate danger signals |
| Alternative | Procedure/proposed mechanism | Evaluation |
|---|---|---|
| Acupuncture | Fine sterile needles placed at selected points; biomedical accounts propose sensory/endorphin modulation while traditional accounts use qi/meridians | Some patients report benefit; practitioner skill, culture/expectancy and condition matter. Bruising/bleeding, infection if unsterile, cost/time and rare injury are limitations |
| TENS | Skin electrodes deliver mild low-voltage current near pain; competing large-fibre input may inhibit transmission and stimulation may recruit endogenous analgesia | Non-drug, adjustable and self-administered for some conditions; placement/dose matter, benefit is not universal, and misuse can irritate/burn skin |
| Clinical need | Reasoned combination |
|---|---|
| Acute injury with continuing danger | Diagnose/protect tissue first; biochemical relief plus brief cognitive support |
| Persistent neuropathic/phantom pain | Specialist review; appropriate medicine and sensory/psychological rehabilitation may be combined |
| Anxiety amplifies procedural pain | Clear information, attention diversion or imagery alongside necessary analgesia |
| Patient seeks acupuncture/TENS | Discuss evidence, contraindications, qualified use, cost and measurable follow-up |
Evaluate the measured outcome: reported intensity, distress, behaviour, function or medication use. Control/placebo comparisons help separate specific mechanism from expectation and attention; objective function can complement self-report, but subjective relief is itself a relevant outcome.
Psychological treatment does not imply unreal pain, and ‘alternative’ does not imply harmless or mechanism-proven. Pain management can be holistic: combine compatible methods while retaining diagnosis, safety and evidence boundaries.